Microcontrollers

2380 Articles

Sucking PIC Firmware Out Of An Old APC Battery Backup

January 18, 2014 by 30 Comments

reverse-engineering-pic-firmware-of-APC-power-supply

Looking at this huge Uninterruptible Power Supply we are a little envious. It’s meant to hang on the wall of a utility room and power your critical devices. [Radek Hvizdos] has had it in service for quite some time, and when he started thinking of replacing the internal battery he decided to see if he could also extend the functionality. To do so he needed to get at the firmware of the chip controlling the device. And so began his adventure of dumping the firmware from the read-protected PIC 18F452.

The challenge of dumping code from a write-protected chip is in itself a fun project. But [Radek] was actually interested in fixing bugs and adding features. The wishlist feature we’d be most interested in is a kind of triage for shutting down devices as the internal battery starts to run low. Nice! But starting from scratch with the firmware is a no-go. You can see the two places where he connected to the PCB. The upper is for using a PIC programmer. The lower is an I2C connection used to dump the EEPROM with an improvised Bus Pirate.

In the end it was improper lock bit settings that opened the door to grabbing the firmware. The bootloader section of the PIC is not locked, and neither is the ability to read from FLASH at run-time. These two combined allowed him to write his own code which, when flashed to the bootloader section, dumps the rest of the firmware so that it may be combined into a complete file afterward. Since posting this fascinating article he has made a follow-up about disassembling the code.

A Light-Up Dress For A New Year’s Dance Party

January 15, 2014 by 5 Comments

wearableLedress

Don’t let the above picture’s lack of blinking colors fool you, the light-up dress [Sam] fashioned for his girlfriend is rather eye-catching; we’d just rather talk about it than edit the gifs he’s provided. [Sam’s] been a busy guy. His last project was a Raspberry Pi digital photo frame, which we featured just over a week ago, but wearable hacks allow him to combine his favored hobbies of sewing and electronics.

If you’re looking to get started with wearable electronics, then this project provides a great entry point. The bulk of the build is what you’d expect: some individually-addressable RGB LEDs, the ever-popular FLORA board from Adafruit, and a simple battery holder. [Sam] decided to only use around 40 of the LEDs, but the strips come 60 to a meter, so he simply tucked the extra away inside the dress and set his desired limits in the software, which will allow him to preserve the entire strip for future projects. If you’ve ever attempted a wearable hack, you’re probably familiar with how delicate the connections can be and how easily the slightest bend in the wiring can leave you stranded. Most opt for a conductive thread solution, but [Sam] tried something different and used 30 AWG wire, which was thin enough to be sewn into the fabric. As an added bonus, the 30 AWG wire is insulated, which permits him to run the wires close to (or perhaps over) each other while avoiding shorts. [Sam’s] guide is detailed and approachable, so head over to his project page if you think you’ve caught wearables fever, and check out his GitHub for the source code.

A Vibrating Timepiece

January 10, 2014 by 21 Comments

vibratingWatch

It may not look like much, but the above pictured device is [qquuiinn’s] handy little watch that indicates time through pulsed vibrations. Perhaps we should refrain from labeling it as a “watch,” however, considering it’s [qquuiinn’s] intention to remove the need to actually look at the thing. Vibrations occur in grandfather clock format, with one long vibration for each hour, accompanied by one, two, or three short pulses for the quarter-hour increments.

The design is straightforward, using an ATTiny85 for the brains along with a few analog components. The vibration motor sticks to the protoboard with some glue, joining the microcontroller, a coin cell battery, and a pushbutton on a small protoboard. The button allows for manual time requests; one press responds with the current time (approximated, probably) in vibrations. The build is a work in progress, and [qquuiinn] acknowledges the lack of an RTC (real-time clock) causes some drift in the timepiece’s accuracy. We suspect, however, that you’d address that problem—twice daily—when you replace the battery: it only lasts ten hours.

3D Bubble Display

January 9, 2014 by 14 Comments

3dbubbledisplay

[Craig Shultz], a mechatronics grad student at Northwestern University, sent us a video of his group’s project from last winter: a 3D bubble display. We’ve seen some pretty impressive and innovative bubble displays around here—most recently the 60-tube RGB LED build—but [Craig’s] is the first we’ve seen that adds some depth to the project.

For the most part, its construction is what you’d expect: an acrylic case enclosing the 4×4 arrangement of tubes, 16 valves 16 individually controlled solenoids, and some small air pumps; all driven by a PIC microcontroller. In the video, however, you’ll have to strain your eyes if you want to see the tubes, which is a clever design choice on [Craig’s] part to showcase the display’s depth. Each of the bubbles was visually separated by pairing glycerin with a tubing material that had a similar index of refraction, Pyrex. As a result, the tubes blend seamlessly into the fluid. Check out the video after the break.

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Mustachioed Rover Simultaneously Manly, Adorable

January 5, 2014 by 24 Comments

[Rick], an Adafruit learning system contributor, is excited by the implications of STEM’s reach into K-12 education. He was inspired to design Red Rover, a low-cost robot that can be easily replicated by anyone with access to a 3-D printer.

This adorable autonomous rover is based on the adafruit Trinket microcontroller, but will also rove under the power of an Arduino micro. It really is quite simple—the Trinket drives two continuous rotation micro servos and pretty much any flavor of rangefinder you like. [Rick] tested it with Parallax PING))), Maxbotix, and Grove sensors, and they all worked just fine.

What’s truly awesome about Red Rover are the track treads. [Rick] initially experimented with flexible filament. While he had good results, it was not a cost-effective solution. What you see in the picture and the short video after the break are actually rubber bracelets from Oriental Trading.

The plastic part count comes in at seven, all of which can be printed together at once. [Rick]’s gallery includes both small and large chassis and three different servo mounts. The Red Rover guide builds on other adafruit guides for Trinket general use, servo modification, and Trinket-specific servo control.

Update: Added [Rick]’s demo video after the break!

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Image Sensor For Filling Wine Bottles

January 5, 2014 by 22 Comments

wine

A wine bottling company in New Zealand got in touch with [Boz] to solve a problem. They needed a way to automatically determine if a wine bottle was filled or not. What he came up with is a very simple yet very effective fill level sensor that can scan thousands of bottles an hour.

There were a few design decisions that went into the construction of this wine bottle sensor. [Boz] could have used a VGA camera sensor, but given the speed of the bottling line (half a meter per second), pushing all those pixels to a computer and doing real-time image analysis would be difficult. [Boz] settled on a much simpler solution – a 1×128 linear CCD analog image sensor. With a PIC microcontroller, this allows the device to check multiple bottles per second, calculate if the bottle is full or not (or overfilled), and send a ‘pass’ or ‘reject’ signal to the rest of the line.

The rest of the assembly is fairly straightforward with an LED backlight providing the illumination for the CCD and a Bluetooth transmitter for checking out the machine’s settings. On the bottling line, the device has 99% accuracy for both red wines in dark bottles and whites in green bottles. You can take a gander of this device in action on a New Zealand bottling line below.

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Once, Twice, Three Times A Nixie

January 2, 2014 by 3 Comments

Try as he might, [Localroger] can’t seem to throw away a certain board that started life in one of the first digital industrial scales, the NCI DigiFlex model 5775. He recently gave it a third career as a nixie clock with an alarm.

[Localroger] says the board dates to about 1975. It’s all TTL, no microprocessor anywhere. He was headed to the Dumpster with it in the mid-1980s, but realized that he could hack it into something useful. Since the display wasn’t multiplexed, it would be fairly easy. He used it as a BCD tester for about 10 years until the method fell out of fashion.

After a decade on the shelf, [Localroger] started off for the Dumpster once more with the board. The nixie tube display cried out for another chance to glow, so he decided to repurpose it into a remote-controlled bedside clock with an alarm. He installed a Parallax Propeller Protoboard with headers for easy removal and subsequent servicing of the 5775 board. He added a few things to the protoboard: a piezo element for the alarm, a SparkFun RTC module, an IR receiver, and vertically-oriented header so the PropPlug can be plugged in from the top. But that’s not all. [Localroger] designed a custom melamine-finished MDF enclosure and laser cut it, giving the edges a nice contrast. It’s so tough, he can put his ceramic lamp on top of it to save space on the nightstand.

Nixie tubes are becoming more scarce all the time. If you can’t find any, we humbly suggest rolling your own.

[Thanks Localroger!]